Potato problems?

Can't see anything on these links - https://ahdb.org.uk/knowledge-library/po...tification and https://ahdb.org.uk/knowledge-library/po...tification - to suggest it's disease. Could be they absorbed too much water during a really wet spell or some other weird weather effect?

I think you may be right. I have checked sites for potato defects and can't find any similar. Just hope this was a one off plant!